[vsnet-grb-info 5272] GRB 20071021: Xinglong TNT optical Upper Limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6962
SUBJECT: GRB 20071021: Xinglong TNT optical Upper Limit
DATE:    07/10/21 17:17:44 GMT
FROM:    L.P. Xin at NAOC  <xlp at bao.ac.cn>

L.P. Xin, M. Zhai, Y.L. Qiu, J.Y. Wei, J.Y. Hu, J.S. Deng,
J. Wang and W.K. Zheng on behalf of EAFON report:
 
We have imaged the field of GRB 071021 (Scott Barthelmy,
GCN 6958) with the TNT 0.8m telescope at Xinglong
Observatory started from  09:55:06.5 UT , 813.8880 after
the burst. A series of White and R band images were
obtained, no new source was found in our combined
image within the error region of the XRT(.Scott
Barthelmy, GCN 6958) and the location reported 
by Andrea Melandri ( Andrea Melandri et al, GCN 6959)

The 3-sigma limit derived from
USNO-B1.0 R2 mag were: 
------------------------------------
Band     Mid time     Exp time  Limit Mag
 
White   0.72 hours     40*20s     20.32 
R      1.38 hours      12*300s    20.85
R      3.25 hours      16*600s    21.69
  
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